US11545826B2ActiveUtilityPatentIndex 54
Electrical power distribution systems with a bypass unit that couples to a load and electrically engages one of two alternate units for powering the load and related methods
Est. expiryJun 28, 2039(~13 yrs left)· nominal 20-yr term from priority
H02H 3/023H02H 7/0822H02H 7/0844
54
PatentIndex Score
0
Cited by
35
References
35
Claims
Abstract
Electrical power distribution systems with a bypass unit that electrically engages one of two alternate units for powering a load while electrically isolating the other using a power transfer switch with first and second contactors and mechanical and electrical interlocks to allow a technician to access one of the alternate units when de-energized and in position while the other of the alternate units is energized and powering the load.
Claims
exact text as granted — not AI-modifiedThat which is claimed is:
1. An electrical power distribution system comprising:
a power bus;
a bypass unit comprising a power transfer switch coupled to a load;
a first unit comprising a first disconnect switch configured to couple the power bus to the power transfer switch; and
a second unit comprising a second disconnect switch configured to couple the power bus to the power transfer switch,
wherein the power transfer switch comprises mechanically interlocked first and second contactors configured to selectively couple only one of the first and second units to the load at any one time,
wherein the bypass unit includes a circuit breaker configured to couple the first unit to the first contactor, wherein the circuit breaker has an operator mechanism configured to be moved between ON and OFF positions to close and open the circuit breaker, respectively, and configured to allow a user to lock the operator mechanism in the ON or OFF position,
wherein, when the first disconnect switch is closed and the power transfer switch couples the first unit to the load, the second disconnect switch is open to electrically isolate the second unit from the load and the first unit, and
wherein, when the first disconnect switch is closed and the power transfer switch couples the second unit to the load, the first disconnect switch is open to electrically isolate the first unit from the load and the second unit,
wherein, at any one point in time during normal operation, the power transfer switch of the bypass unit is configured to electrically connect the power bus to the load using only one of the first unit or the second unit,
wherein, when the power transfer switch couples the first unit to the load, the first disconnect switch is closed while the second disconnect switch is open to electrically isolate the second unit from the load and the first unit, and
wherein, when the power transfer switch couples the second unit to the load, the second disconnect switch is closed while the first disconnect switch is open to electrically isolate the first unit electrically from the load and the second unit.
2. The electrical power distribution system of claim 1 , wherein the first and second units each further comprise a housing and a power disconnect assembly with extendable/retractable power stabs that independently move relative to the housing to connect to and disconnect from the power bus, and wherein the extendable/retractable power stabs of only one of the first unit or the second unit is permitted to be connected to the power bus at any one time.
3. The electrical power distribution system of claim 1 , wherein the bypass unit comprises a housing with a front wall, side walls and a rear wall and is devoid of power stabs and does not directly connect to the power bus.
4. The electrical power distribution system of claim 1 , wherein each of the bypass unit, the first unit and the second unit includes a separate housing that is independently insertable and removable from a respective compartment in at least one structure of the electrical distribution system.
5. The electrical power distribution system of claim 1 , wherein the first unit further comprises a first motor starter and the second unit further comprises a second motor starter, and wherein the electrical power distribution system further comprises at least one structure with defined spaced-apart internal compartments that hold the bypass unit, the first unit and the second unit in different ones of the defined spaced-apart internal compartments, wherein the first unit comprises a first front door with a first disconnect operator handle operably coupled to the first disconnect switch, wherein the second unit comprises a second front door with a second disconnect operator handle operably coupled to the second disconnect switch, and wherein the electrical power distribution system further comprises interlocks that (a) prevent the first door from opening when either the first disconnect switch is closed or the first unit is coupled to the load and (b) prevent the second door from opening when either the second disconnect switch is closed or the second unit is coupled to the load.
6. The electrical power distribution system of claim 1 , wherein the bypass unit and the first and second units are configured to be insertable and removable from spaced-apart compartments of a structure defining internal compartments, wherein the second electrical path in the bypass unit is devoid of a circuit breaker, and wherein the bypass unit further comprises a manually activatable back-up bypass path as a third path in the bypass unit comprising a circuit breaker that connects the load to the second unit without requiring the second path from the second contactor, optionally wherein the third path and the second path merge in the bypass unit to a common conductor output from the bypass unit, wherein the common conductor output is configured to couple to the second unit.
7. The electrical power distribution system of claim 1 , wherein the first and second disconnect switches are circuit breakers, and wherein at least one of the bypass unit or the first and second units are electrically coupled to cause a first one of either the first disconnect switch or the second disconnect switch to trip to an open state when a second one of the first disconnect switch or the second disconnect switch is closed to allow conduction whereby only a single one of the first or second disconnect switch is closed at any one time.
8. The electrical power distribution system of claim 1 , wherein the electrical distribution device is a motor control center (MCC).
9. The electrical power distribution system of claim 1 , wherein the first disconnect switch and the second disconnect switch each comprise a circuit breaker, and wherein the power transfer switch comprises auxiliary switches that are configured to automatically transmit a trip signal to the first unit prior to or concurrently with engaging the second contactor.
10. The electrical power distribution system of claim 1 , further comprising a relay system associated with the first unit, wherein the relay system is configured to detect a malfunction or power off event of the first unit and responsively (i) trip open the circuit breaker and open the first contactor to decouple the first unit from the load and (ii) close the second contactor to couple the second unit to the load and automatically transfer power from the power bus to the second unit and the second electrical path and to the load and (ii) automatically directly or indirectly via an auxiliary switch transmit a control signal to the circuit breaker in the bypass unit to cause the circuit breaker to trip.
11. The electrical power distribution system of claim 1 , wherein the first unit and the second unit are provided as one of options A-L:
Option
first unit
second unit
A
VFD unit
VFD unit
B
Soft Starter
Soft Starter
(Reduced Voltage
(Reduced Voltage
starter) unit
starter) unit
C
NEMA Starter unit
NEMA Starter unit
D
IEC Starter unit
IEC Starter unit
E
VFD unit
Soft Starter
(Reduced Voltage
starter) unit
F
Soft Starter
NEMA Starter unit
(Reduced Voltage
starter) unit
G
NEMA Starter unit
IEC Starter unit
H
VFD unit
NEMA Starter unit
I
Soft Starter
IEC Starter unit
(Reduced Voltage
starter) unit
J
VFD unit
IEC Starter unit
K
Feeder Breaker
Feeder Breaker
L
Feeder Fused
Feeder Fused.
12. The electrical power distribution system of claim 1 , wherein the bypass unit further comprises a first conductor coupled to switch contacts of the first contactor, a second conductor coupled to switch contacts of the second contactor, and a third conductor configured to couple to the load and the first and second contactors, the first conductor extending from the bypass unit a distance sufficient to couple to the first unit, the second conductor extending from the bypass unit a distance sufficient to couple to the second unit, and the third conductor extending from the bypass unit and having a length sufficient to couple to the load.
13. The electrical power distribution system of claim 12 , wherein the first and second conductors extend from the bypass unit through a wire way to connect to the respective first and second units.
14. The electrical power distribution system of claim 1 , wherein the electrical power distribution device is a motor control center (MCC), wherein the first and second units each further comprise a housing and a power disconnect assembly with extendable/retractable power stabs that independently move relative to the housing to connect to and disconnect from the power bus, wherein the extendable/retractable power stabs of only one of the first and second units are permitted to be connected to the power bus at any one time, and wherein the first unit and the second unit each comprise a lock that, when deployed, physically (a) locks the power disconnect assembly in at least one defined position associated with one or both (i) a retracted position associated with an electrically isolated state of the respective unit or (ii) an extended position associated with engagement with the power bus and an electrically active state, and/or (b) locks a laterally movable slide from allowing access to an aperture that allows a crank to change a position of the power stabs.
15. The electrical power distribution system of claim 14 , further comprising at least one interlock that is configured to allow a user to open and/or remove the first unit from the MCC only when the first unit is in the electrically isolated state and the circuit breaker in the bypass unit is open while allowing the second unit to be energized, connected to the power bus to provide power to the load through the second contactor of the bypass unit.
16. The electrical power distribution system of claim 1 , wherein each of the first and second units is independently insertable and removable from a respective compartment of a structure of the electrical distribution system and each is serially interchangeable with a different corresponding unit having a common size and shape housing thereby allowing modular repair and replacement, and wherein the bypass unit is held in a housing with a closed front door and has a height that is in a range of about 6-12 inches.
17. The electrical power distribution system of claim 1 , wherein the bypass unit, the first unit and the second unit are held in separate housings, wherein the bypass unit, the first unit and the second unit are configured to power a load with horsepower in a range of about ¼ horsepower to 200 horsepower, and wherein the bypass unit has a closed front door with a front operating switch handle coupled to the power transfer switch.
18. The electrical power distribution system of claim 1 , wherein the power transfer switch of the bypass unit further comprises at least one auxiliary switch, and wherein the at least one auxiliary switch is configured to transmit and/or receive control signals to/from at least one of the first or second units.
19. The electrical power distribution system of claim 1 , wherein the first disconnect switch includes a first circuit breaker and the second disconnect switch includes a second circuit breaker, and wherein the first and second circuit breakers and the power transfer switch are electrically interlocked, such that, when the power transfer switch couples one of the first and second units to the load, only the associated first or second circuit breaker can be closed.
20. The electrical power distribution system of claim 19 , wherein the power transfer switch further comprises at least one auxiliary switch coupled to the circuit breakers that is configured to transmit a trip signal to the circuit breaker of the first disconnect switch when the power transfer switch couples the second unit to the load.
21. A method of assembling an electrical distribution system, comprising;
providing a bypass unit in a housing comprising a power transfer switch configured to couple to only one of first and second separate units held in separate respective housings to a load at any one time, wherein the power transfer switch comprises mechanically interlocked first and second contactors configured to selectively couple the first and second units to the load where only one of the first and second contactors close at any one time, wherein the bypass unit further comprises a circuit breaker coupled between the first unit and the first contactor to thereby inhibit electrical feedback to the first unit when the second contactor is closed and the second unit is energized, wherein the circuit breaker has an operator handle configured to be moved between ON and OFF positions to close and open the circuit breaker, respectively, and configured to allow a user to lock the operator mechanism in the ON or OFF position; and
selecting only two units as the first and second units to connect to the bypass unit from one of options A-L:
Option
first unit
second unit
A
VFD unit
VFD unit
B
Soft Starter
Soft Starter
(Reduced Voltage
(Reduced Voltage
starter) unit
starter) unit
C
NEMA Starter unit
NEMA Starter unit
D
IEC Starter unit
IEC Starter unit
E
VFD unit
Soft Starter
(Reduced Voltage
starter) unit
F
Soft Starter
NEMA Starter unit
(Reduced Voltage
starter) unit
G
NEMA Starter unit
IEC Starter unit
H
VFD unit
NEMA Starter unit
I
Soft Starter
IEC Starter unit
(Reduced Voltage
starter) unit
J
VFD unit
IEC Starter unit
K
Feeder Breaker
Feeder Breaker
L
Feeder Fused
Feeder Fused.
22. The method of claim 21 , wherein the first and second units each comprise a power disconnect assembly having extendable/retractable power stabs.
23. The method of claim 21 , further comprising:
slidably inserting the bypass unit and the selected first and second units into compartments of a structure of the electrical distribution system; and
electrically connecting the power transfer switch of the bypass unit to the selected first and second units during, before or after the inserting.
24. The method of claim 23 , wherein the electrical distribution system is a Motor Control Center.
25. The method of claim 21 , wherein the selected first and second units and the bypass unit each have a dedicated, respective front door, and wherein the bypass unit has a closed rear panel with a plurality of conductors extending outward therefrom including an conductor that couples to a load, and conductors that couple to the selected first and second units.
26. The method of claim 21 , wherein the power transfer switch of the bypass unit comprises at least one auxiliary switch attached thereto, and wherein the at least one auxiliary switch is configured to transmit and/or receive control signals to/from at least one of the first or second units.
27. The method of claim 21 , wherein a first set of three switch contacts of the first contactor are coupled only to the first unit while a second set of three switch contacts of the second contactor, different from the first set of three switch contacts, are coupled only to the second unit to thereby serially couple the load to the first unit and the second unit via the bypass unit, and optionally wherein the bypass unit further comprises a manually activatable back-up bypass path with a circuit breaker that connects the load to the second unit.
28. A bypass unit for an electrical power distribution system having a structure defining a plurality of separate compartments including first, second and third compartments, the first compartment having a first unit installable therein and the second compartment having a second unit installable therein, the bypass unit comprising:
a housing configured to be insertable and removable from the third compartment;
a bypass circuit with a power transfer switch in the housing, wherein the power transfer switch comprises mechanically interlocked first and second contactors configured to selectively couple to a load and define first and second electrical paths where only one of the first and second contactors close at any one time, wherein the bypass unit further comprises a circuit breaker in the bypass unit coupled to the first electrical path, wherein the circuit breaker has an externally accessible operator handle that faces a front of the bypass unit and is configured to allow a user to lock the handle in an off position associated with an open state of the circuit breaker and non-conduction in the first electrical path;
a first conductor coupled to a first set of three switch contacts of the first contactor and extending out of the housing;
a second conductor coupled to a second set of three switch contacts of the second contactor and extending out of the housing; and
a third conductor coupled to a load side of the power transfer switch and extending out of the housing with a length sufficient to couple to a load;
wherein the first conductor is configured to electrically couple to the first unit and the second conductor is configured to electrically couple to the second unit.
29. The bypass unit of claim 28 , wherein the housing has a height in a range of about 6-12 inches.
30. The bypass unit of claim 28 , wherein the power transfer switch is configured to power the load from a power bus using the second unit only when a disconnect switch of the first unit and the circuit breaker of the bypass unit are closed and in an off state associated with non-conduction to thereby provide electrical isolation of the first unit allowing a user to access or remove the first unit from the structure while the second unit is powering the load through the bypass unit.
31. The bypass unit of claim 28 , wherein the housing is rectangular and configured to be insertable and removable from the third compartment.
32. The bypass unit of claim 28 , further comprising at least one auxiliary switch in the bypass unit coupled to the power transfer switch, wherein the at least one auxiliary switch is configured to transmit and/or receive control signals to/from at least one of the first or second units.
33. The bypass unit of claim 28 , further comprising a manually activatable back-up bypass path with a circuit breaker that is configured to connect the load to the second unit as a back-up to the second contactor, wherein the circuit breaker of the back-up bypass path comprises an operator handle, and wherein only one of the circuit breaker of the back-up bypass path and the circuit breaker coupled to the first contactor is closed at any one time.
34. A method of transferring power from one unit to another unit to power a load using a motor control center (MCC), comprising:
providing an MCC with a power bus, a first unit having a first housing, a second unit having a second housing and a bypass unit having a bypass unit housing, the bypass unit housing comprising a power transfer switch configured to couple a load to a single one of the first and second units at any one time to thereby provide a redundant power source for the load;
mechanically interlocking first and second contactors of the power transfer switch to selectively couple only one of the first and second contactors to the load at any one time
providing in the bypass unit a circuit breaker coupled between the first unit and the first contactor;
electronically detecting a power failure or malfunction of the first unit;
automatically opening the circuit breaker in the bypass unit;
automatically opening a disconnect switch in the first unit; and
automatically opening the first contactor of the power transfer switch and closing the second contactor to power the load using the second unit.
35. The method of claim 34 , further comprises allowing a user to manually engage a back-up bypass path comprising a circuit breaker that connects the load to the second unit, wherein the disconnect switch in the first unit is interlocked in an open position in response to the manual engagement.Cited by (0)
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